Hydrocratic generator

ABSTRACT

A mixing apparatus for mixing first salinity fluid with a second salinity fluid, the mixing apparatus comprises a down tube having a side wall, an open upper end and an open lower end, and a plurality of apertures selectively located in the side wall of the down tube. At least some of the apertures have an arm with an opening therein about the aperture to facilitate inflow of fluid to the down tube through the openings. A fluid inlet and a fluid outlet are provided at the open upper end and open lower end respectively of the down tube so that the first salinity fluid in use enters the down tube through the fluid inlet and the apertures and is discharged therefrom through the fluid outlet. A feed tube is provided and has a first end connectable to a source of second salinity fluid having a salinity different to the first salinity fluid and a second end for introducing the second salinity fluid to the fluid inlet of the down tube to mix the first salinity fluid with the second salinity fluid to form a fluid mixture.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part application of U.S. patent application Ser. No. 11/158,832 filed Jun. 21, 2005, which is a continuation-in-part of U.S. patent application Ser. No. 11/096,981 filed Mar. 31, 2005, which is a continuation-in-part application of U.S. patent application Ser. No. 10/777,458 filed Feb. 12, 2004, which is a continuation-in-part application of U.S. patent application Ser. No. 10/357,007 filed Feb. 3, 2003 and also a continuation-in-part of U.S. patent application Ser. No. 10/404,488 filed Mar. 31, 2003. U.S. patent application Ser. No. 10/357,007 is continuation-in-part of, and U.S. patent application Ser. No. 10/404,488 is a continuation of, U.S. patent application Ser. No. 09/952,564 filed Sep. 12, 2001, now U.S. Pat. No. 6,559,554, which is a continuation-in-part of U.S. patent application Ser. No. 09/415,170 filed Oct. 8, 1999, now U.S. Pat. No. 6,313,545. U.S. patent application Ser. No. 09/415,170 itself claims the benefit of Provisional Patent Applications Nos. 60/123,596 filed Mar. 10, 1999 and 60/141,349 filed Jun. 28, 1999. All of the above applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to hydraulic power generation systems and, in particular, to an apparatus and method for generating power using a novel pseudo-osmosis process which efficiently exploits the osmotic energy potential between two bodies of water having different salinity concentrations.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect to provide an improved apparatus and method for generating power using a novel forward osmosis process which efficiently exploits the osmotic energy potential between two bodies of water having different salinity concentrations.

Advantageously, the method and apparatus of the present invention does not require the use of a semi-permeable membrane or other specially formulated material, nor does it require heating or cooling of the fresh water or salt water solution. Moreover, the present invention may recover energy from a wide variety of fresh water sources, including treated or untreated river run-off, treated waste-water run-off or effluent, storm-drain run-off, partly contaminated fresh water run-off, and a wide variety of other fresh water sources. Thus, the present invention is well suited to large scale power production in a wide variety of geographic locations and under a wide variety of conditions. The invention has particular advantage for use in remote regions where electrical power generation by conventional means may be commercially infeasible or impractical.

According to one aspect of the invention, there is provided a mixing apparatus for mixing first salinity fluid with a second salinity fluid, the mixing apparatus comprising: a down tube having a side wall, an open upper end and an open lower end, and a plurality of apertures selectively located in the side wall of the down tube, at least some of the apertures having an arm member with an opening therein about the aperture to facilitate inflow of fluid to the down tube through the openings; a fluid inlet and a fluid outlet at the open upper end and open lower end respectively of the down tube, wherein the first salinity fluid in use enters the down tube through the fluid inlet and the apertures and is discharged therefrom through the fluid outlet; and a feed tube having a first end connectable to a source of second salinity fluid having a salinity different to the first salinity fluid and a second end for introducing the second salinity fluid to the fluid inlet of the down tube to mix the first salinity fluid with the second salinity fluid to form a fluid mixture.

According to another aspect of the invention, there os provided a hydrocratic generator system comprising: a container having an upper chamber and a lower chamber sealed from the upper chamber, the upper chamber for accommodating a body of fluid having a first salinity; a first feed inlet in the upper chamber of the container through which the fluid having a first salinity can be discharged into the container; a down tube having an upper inlet end and a lower outlet end, the down tube being located primarily in the upper chamber of the container with the outlet end thereof discharging into the lower chamber; a second feed inlet through which fluid having a second salinity can be discharged into the upper chamber of the container such that the fluid having the second salinity mixes with the fluid having the first salinity in the down tube; and a discharge means from the lower chamber to facilitate discharge of the mixed fluids.

According to yet another aspect of the invention, there is provided a mixing apparatus for mixing first salinity fluid with a second salinity fluid, the mixing apparatus comprising: a down tube having a side wall and an open upper end and an open lower end, the down tube having a funnel shaped portion at the upper end, a cylindrical portion below the funnel shaped portion, a substantially square portion below the cylindrical portion and a venturi tube portion below square portion.

In yet another aspect of the invention, there is provided a mixing apparatus for mixing first salinity fluid with second salinity fluid, the mixing apparatus comprising: a down tube having a side wall and an open upper end and an open lower end, the side wall being comprised of a meshed screen portion and solid portion below the meshed screen portion; a fluid inlet and a fluid outlet at the open upper end and open lower end respectively of the down tube, wherein the first salinity fluid in use enters the down tube through the fluid inlet and meshed screen portion and is discharged therefrom through the fluid outlet; a feed tube having a first end connectable to a source of second salinity fluid having a salinity different to the first salinity fluid and a second end for introducing second salinity fluid to the fluid inlet of the down tube to mix the first salinity fluid with the second salinity fluid to form a fluid mixture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram representation of a conventional forward osmosis process through a semi-permeable membrane;

FIG. 1B is a schematic diagram representation of a conventional reverse osmosis process through a semi-permeable membrane;

FIG. 2 is a schematic representation of an experimental up tube upwelling apparatus for use in accordance with the present invention;

FIG. 3 is a graph of theoretical power recovery for different sized down-tubes and fresh water flow rates using the experimental upwelling device of FIG. 2;

FIG. 4 is a schematic representation of one embodiment of a hydrocratic generator having features and advantages in accordance with the present invention;

FIG. 5 is a schematic representation of an alternative embodiment of a hydrocratic generator having features and advantages in accordance with the present invention;

FIG. 6 is a schematic representation of a further alternative embodiment of a hydrocratic generator having features and advantages in accordance with the present invention;

FIG. 7A is a schematic representation of a further alternative embodiment of a hydrocratic generator having features and advantages in accordance with the present invention;

FIG. 7B is a side view of the up tube of FIG. 7A, showing the slots in the side of the up tube;

FIG. 7C is a sectional view from below of the shaft support of FIG. 7A;

FIG. 7D is a sectional view from above of the vane drum of FIG. 7A;

FIG. 8A is a schematic representation of a further alternative embodiment of a hydro-osmotic generator having features and advantages in accordance with the present invention;

FIG. 8B is a side view of the up tube of FIG. 8A showing two sets of slots in the side of the up tube;

FIG. 8C is a sectional view from below of the shaft support of FIG. 8A;

FIG. 8D is a sectional view from above of the vane drum of FIG. 8A;

FIG. 9A is a schematic view of an up tube with an open lower end with an alternative embodiment of a down tube having a plurality of holes in the sides and the outlet end, having features and advantages in accordance with the present invention;

FIG. 9B is a sectional view from below of the up tube and the outlet end of the down tube of FIG. 9A;

FIG. 10A is a schematic view of an up tube with an open lower end with an alternative embodiment of the down tube with a plurality of secondary down tubes having holes in the sides and the outlet end, having features and advantages in accordance with the present invention;

FIG. 10B is a sectional view from below of the up tube and the outlet end of the down tube of FIG. 10A showing the plurality of secondary down tubes and the holes on the outlet ends of the secondary down tubes;

FIG. 11 is a schematic view of an up tube with an open lower end with an alternative embodiment of the down tube with a plurality of secondary down tubes, having features and advantages in accordance with the present invention;

FIG. 12 is a schematic view of a down tube with a rotating hub and spoke outlets with no up tube;

FIG. 13 is a schematic view of a down tube with a rotating hub and spoke outlets with an up tube, having features and advantages in accordance with the present invention;

FIG. 14 is a schematic view of a portion of an up tube comprising a plurality of concentric up tubes, having features and advantages in accordance with the present invention;

FIG. 15 is a schematic representation of a modified up tube having features and advantages in accordance with the present invention;

FIG. 16 is a schematic illustration of a possible large-scale commercial embodiment of a hydro-osmotic generator having features and advantages in accordance with the present invention;

FIG. 17 is a cutaway view of the turbine and generator assembly of the hydro-osmotic generator of FIG. 12;

FIG. 18 is a schematic view of an up tube with an open lower end, with an alternative embodiment of the rotating down tube, extending substantially into the up tube, and having holes and turbines mounted thereon, having features and advantages in accordance with the present invention;

FIG. 19A is a schematic view of an up tube with a closed lower end, with an alternative embodiment of the rotating down tube, extending substantially into the up tube, and having holes and turbines mounted thereon, having features and advantages in accordance with the present invention;

FIG. 19B is a side view of the up tube shown in FIG. 19A;

FIG. 20 is a schematic view of an up tube with an open lower end, with an alternative embodiment of the rotating down tube, extending substantially into the up tube, and having holes and turbines mounted thereon, with rotating up tube and down tube, having features and advantages in accordance with the present invention;

FIG. 21 is a schematic view of an up tube upwelling apparatus in accordance with the present invention wherein a rotating helical screw is used to generate the power instead of a plurality of fan blades, having features and advantages in accordance with the present invention;

FIG. 22A is a side view of an alternative embodiment of a fan blade used in accordance with the present invention;

FIG. 22B is a schematic view showing the under portion of the fan blade illustrated in FIG. 22A of the drawings;

FIG. 23 is a schematic representation showing a further device of the invention, including multiple turbines;

FIG. 24 a is a schematic representation of yet a further embodiment of the invention, including a wrapped tube;

FIG. 24 b is a cross-section through a part of the apparatus as shown in FIG. 24 a;

FIG. 25 is a schematic representation showing yet a further embodiment of the invention, including a sleeve tube;

FIG. 26 is a schematic representation showing yet a further embodiment of the invention including a plurality of differently located feed tubes;

FIG. 27 a is a schematic representation showing a further embodiment of the invention, including feed tubes incorporating rings;

FIG. 27 b is a schematic representation showing a cross-section through the device of the invention as shown in FIG. 27 a;

FIG. 28 is a schematic representation of yet a further embodiment of the invention used in the context of a power generator using sewage or sanitation effluent and may use a brine line from a water desalinization plant;

FIG. 29 is a schematic view of a further embodiment of the hydrocratic generator of the invention;

FIG. 30 is a schematic view of yet a further embodiment of the hydrocratic generator of the invention; and

FIG. 31 is a view from the bottom of the brine line shown in FIG. 30 of the drawings;

FIG. 32 is a schematic top view of a further embodiment of a hydrocratic generator in accordance with the invention;

FIG. 33 is a side view of the hydrocratic generator shown in FIG. 32 of the drawings;

FIG. 34 is a top view of a further embodiment of a hydrocratic generator in accordance with the principles of the invention;

FIG. 35 is a side view of the hydrocratic generator shown in FIG. 34 of the drawings;

FIG. 36 is a schematic side view of a hydrocratic generator in accordance with another embodiment of the invention;

FIG. 37 is a schematic side view of a still further embodiment of a hydrocratic generator in accordance with the present invention;

FIG. 38 is a schematic side view of still a further embodiment of the hydrocratic generator of the invention;

FIG. 39 is a schematic view of a tube with substantially uniform diameter;

FIG. 40 is a schematic view of a tube having a tapering diameter;

FIG. 41 is another schematic view of a tube having a tapering diameter and a series of successively wider tubes;

FIG. 42 is a schematic representation of yet another embodiment of the invention;

FIG. 43 is a schematic view of a hydrocratic generator in accordance with another embodiment of the invention, contained in a reservoir;

FIG. 44 is a schematic view of a hydrocratic generator in accordance with another embodiment of the invention, when constructed in the ocean;

FIG. 45 is a schematic illustration of a hydrocratic engine with features and structure in accordance with yet a further embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

When solvent fluids having differing osmotic potentials are contacted and mixed with each other energy is released. This released energy results from an increase in entropy of water (or other solvent) when it is transformed from its pure (fresh-water) state to its diluted (salt-water) state. Thus, an entropy gradient is created whenever two bodies of water or other solvents having differing solute concentrations are brought into contact with one another and begin to mix. This entropy gradient can be physically observed and measured in the well-known phenomena known as osmosis.

Because the term “osmosis” is associated with a membrane, the term “hydrocrasis” is used as a term for the situation when solvent fluids having differing osmotic potentials are contacted and mixed with each other in the absence of a membrane.

FIG. 1A schematically illustrates conventional forward osmosis through a semi-permeable membrane. Forward osmosis results in the flow of water 10 (or other solvent) through a selectively permeable membrane 12 from a lower concentration of solute 14 to a higher concentration of solute 14.

FIG. 1B illustrates the condition of reverse osmosis whereby water (or other solvent) 10 under the influence of external pressure is forced through a selectively permeable membrane 12 from a higher concentration of solute 14 to a lower concentration of solute 14, thus squeezing out or extracting the pure solvent 10 from the solute 14. Reverse osmosis is widely used in water purification and desalinization plants throughout the world. Reverse osmosis consumes work energy.

The osmotic energy potential to be gained from remixing fresh water into saline ocean water is significant—about 1.4 kJ/kg of fresh water, or the equivalent of about 290 m-head of water for a conventional hydropower system. If this source of stored energy could somehow be efficiently exploited, it could result in the production of enormous amounts of inexpensive electrical power from a heretofore untapped and continually renewable energy resource.

During recent prototype testing of a similar upwelling device it was discovered, surprisingly, that the amount of upwelling flow achieved in terms of kinetic energy of the overall mass flow was in excess of the input energy into the system in terms of the buoyancy effect and kinetic energy resulting from the fresh water introduced into the up tube. Subsequent experiments using a modified upwelling device have confirmed that the total hydraulic energy output of such system significantly exceeds the total hydraulic energy input.

While an exact explanation for this observed phenomena is not fully appreciated at this time, it is believed that the excess energy output is somehow attributable to the release of osmotic energy potential upon remixing of the fresh water and the salt water in the up tube.

Example 1

The apparatus shown in FIG. 2 was used to measure observed flow rates in the up tube 40 with different fresh water flow rates introduced into the down tube 20. Table 1 is a compilation of the results for flow rates at various points in the up tube 40 with two different flow rates of fresh water in the down tube 20. The flow rate at Point 1, the flow rate of fresh water from the reservoir, and the salinity at Point 2 at the outlet end 44 of the up tube 40 were measured parameters. The flow rate at Point 3, the outlet end 24 of the down tube 20, was the same as the flow rate at Point 1. The remaining flow rates were calculated using the equations discussed above.

TABLE 1 Flow Rates at Various Locations in the Up Tube Height of Salinity Reservoir at Point 2 Flow (10⁻⁴ m³/sec) (meters) (ppt) Point 1 Point 2 Point 3 Point 4 0.23 34 1.3 45.5 1.3 44.2 0.55 34 2.4 84.0 2.4 81.6

The results indicate that the flow rate of the mixed salt-water/fresh-water solution at Point 2 at the outlet end 44 of the up tube 40 far exceeded the flow rate of fresh water at Point 1 and Point 3. Introducing fresh water into the down tube 20 and allowing the salt water to flow into the up tube 40 therefore generated higher flow rates at Point 2, at the top of the up tube 40.

In order to demonstrate that this higher flow rate at Point 4 was not due to transfer of kinetic energy from the fresh water flow coming from the down tube 20, the following experiment was performed.

Example 2 Flow Rates Through the Up Tube with Salt Water vs. Fresh Water Introduced into the Down Tube

For this experiment, a 6″ turbine roof vent was attached to the outlet end 44 of the up tube 40. One of the vanes was painted to allow for the counting of rotations. The reservoir was filled with fresh water having a salinity of 300 ppm in one experiment and with salt water having a salinity of 36,000 ppm in a second experiment. The reservoir was placed at a height of 0.55 meters above the water level of the salt water in the pool. The fresh water was then allowed to flow through the down tube 20, and the rate at which the turbine rotated was determined. Then, salt water from the salt water pool was allowed to flow through the down tube 20, and the rate at which the turbine rotated was again determined. The results are shown in Table 2 below

TABLE 2 Turbine Speed with Fresh Water vs. Salt Water in Down Tube Down Tube Water Flow Turbine Speed (10⁻⁴ m³/sec) (rpm) Fresh Water (0.3 ppt) 2.4 5.6 Salt Water (36 ppt) 2.3 2.3

As illustrated in Table 2, above, the turbine rotated 2.4 times more rapidly when fresh water was introduced into the down tube 20 than when salt water was used. The higher turbine speed when fresh water was introduced into the down tube 20 is a direct indication that the water flow in the up tube 40 was higher when fresh water rather than salt water was introduced into the down tube 20 and that the higher observed water flow rates from the top of the up tube 40 in Example 1 were not due solely to kinetic energy transfer from the fresh water flow out of the down tube 20.

The kinetic energy transferred from the salt water in the down tube 20 to the salt water in the up tube 40 would be at least as great (if not slightly greater due to increased density of salt water) as the kinetic energy transferred from the fresh water in the down tube 20. The results shown in Table 2 indicate that some, but not all, of the upwelling of water in the up tube 40 is due to kinetic energy transfer from the water introduced into the down tube 20.

Example 3

A series of experiments were carried out using the experimental design described above and as illustrated in FIG. 2, but with down tubes 20 having different diameters. With each down tube 20, the flow rates of the fresh water in the down tube 20 were varied to determine the effect of different fresh water flow rates on available power. The salinity at the outlet end 44 of the up tube 40 was measured, and the water flow rates were calculated from the salinity as before. The water flow rates were used to calculate the available power at Point 2, the outlet end 44 of the up tube 40. The available power was then normalized by dividing the available power by the fresh water flow rate in the down tube 20. The results are shown in Table 4 below.

TABLE 4 Normalized Power Production vs. Diameter of Up Tube and Fresh Water Flow Rates Down Ratio of Up Power/Fresh Salinity Flow (×0.0001 m³) Tube Tube Area to Water at Point Point Point Area Down Tube Flow 2 (ppt) Point 1 4 2 (m²) Area (Watts/m³) 31.8 22 259 281 0.000254 69.7 1312 32.6 18 309 327 0.000071 249 2715 33.4 5.2 158 163 0.000018 983 1256 31.4 33 334 367 0.000254 69.7 1877 32.6 26 446 472 0.000071 249 5664 33.3 7.6 211 218 0.000018 983 2047 35.0 5 168 173 0.000010 1770 1559

In all cases, the power per unit volume of fresh water introduced into a down tube 20 of a given diameter increased as the flow rate of fresh water through the down tube 20 increased. Thus, for the down tube 20 with an area of 0.000254 m², the power/m³ of fresh water flow increased from 1312 watts/m³ with a fresh water flow rate of 22×10⁻⁴ m³ to 1877 watts/m³ with a fresh water flow rate of 33×10⁻⁴ m³. The same trend was maintained for the down tubes having areas of 0.000071 and 0.000018 m². Thus, the data illustrates that increasing the fresh water flow rate in a down tube 20 having a given area increased the normalized available power output of the device.

Second, although the power per unit volume of fresh water introduced into the down tube 20 increased with increased volume of fresh water introduced into the down tube 20 in all cases, the percent increase in the power with increase in fresh water flow rate was less for the largest down tube 20 (0.000254 m² area) than for the other down tubes 20. When the fresh water flow rate increased from 22×10⁻⁴ m³/sec to 33×10⁻⁴ m³/sec, or by 50%, with the largest down tube 20, the power/fresh water flow rate increased from 1312 watts/m³ to 1877 watts/m³, or 40%. By comparison, when the fresh water flow rate for the down tube 20 with an area of 0.000018 m²/sec was increased from 5.2 to 7.6×10⁻⁴ m³/sec, or 46%, the power/fresh water flow rate increased from 1256 watts/m³ to 2047 watts/m³, or 62%, more than 1.5 times as much as for a comparable percent change in the fresh water flow rate with the larger down tube 20.

Similarly, when the fresh water flow rate for the down tube 20 with an area of 0.000071 m³ increased from 18 to 26×10⁻⁴ m³/sec, or 44%, the power/fresh water flow rate increased from 2715 watts/m³ to 5664 watts/m³ or 108%, more than 2.5 times as much as for the largest down tube 20. The efficiency of power production declined with the largest diameter down tube 20.

These results are shown graphically in FIG. 3. The graphs depicted therein appear to show that there is an optimum ratio (about 250:1) of the area of the up tube 40 relative to the area of the down tube 20 that maximizes normalized power production. At ratios higher or lower than about 250 the normalized power per unit volume of fresh water declines.

Although a ratio of the area of the up tube 40 relative to the area of the down tube 20 of approximately 250 appears to be optimal, the ratio may range from approximately 5 to 50,000, more preferably from 50 to 2000.

The previous examples and discussions illustrate that a suitably constructed upwelling apparatus as illustrated in FIG. 2 has the potential of generating useful power by mixing aqueous liquids having different osmotic potentials.

FIG. 4 is a simple schematic illustration of one possible embodiment of a hydrocratic generator 100 utilizing the principles discussed above and having features and advantages in accordance with the present invention. The device 100 generally comprises a down tube 20, an up tube 40, and a power plant generator 60. The particular device illustrated in FIG. 4 may be adapted for either large-scale deep water applications or for relatively small-scale or intermediate-scale power generation facilities in shallow coastal waters, as desired. For example, the depth of water illustrated in FIG. 4 may be 10 to 50 meters or more, with the up tube 40 being 1-5 meters in diameter.

In a preferred embodiment, fresh water is introduced into the down tube 20 in order to power the device. The term “fresh” water as used herein is to be interpreted in a broad sense as water having an osmotic potential relative to sea water. Thus, it may be used to describe the input stream a river discharge, a mountain run-off, a treated sewage discharge, a melting iceberg, or even runoff from a city storm drainage system.

The fresh-water input stream may be conducted though the down tube 20 by applying pressure at the inlet end 22 of the down tube 20. The pressure may be provided by a pumping station or with a hydrostatic head pressure resulting from a fluid reservoir at a higher elevation. The pressure applied at the inlet end 22 of the down tube 20 need only be high enough to overcome the hydrostatic head at the outlet end 24 of the down tube 20.

It has been found that, when fresh water is introduced into the down tube 20, sea water flows into the up tube 40, causing upwelling in the up tube 40 that can be used to generate power with the power generator 60. Some of this upwelling effect is due to the increased buoyancy of the mixed water in the up tube 20, because fresh water has a lower density than sea water. However, far more upwelling of sea water is observed than would be expected from this phenomenon alone. It is believed that the apparatus and the method is able to harness the energy available from the different osmotic potentials of fresh water and sea water. The amount of upwelling and the amount of power that is generated in the device depend in part on the particular dimensions of the up tube 40 and the down tube 20 and the flow rate of fresh water in the down tube 20.

As shown in FIG. 4, the down tube 20 has an inlet end 22 and an outlet end 24. The inlet end 22 is connected to a supply 25 of relatively fresh water. For example, this fresh water supply 25 may comprise a reservoir, pump or other source as desired or expedient. The outlet end 24 of the down tube 20 is open such that the fresh water discharges through the outlet end 24 of the down tube 20 into the up tube 40. In alternative embodiments the outlet end 24 of the down tube 20 may be connected to an intermediate mixing chamber (not shown) which then discharges into the up tube 40.

Although the down tube 20 may be any of a variety of diameters, one criterion is to choose a diameter for the down tube 20 which minimizes the resistance to fluid flow through the down tube 20. Resistance to flow through a tube decreases as the diameter of the tube increases. Choosing a large diameter for the down tube 20 therefore minimizes the resistance of the tube for a given flow rate.

Another criterion in choosing the diameter of the down tube 20 is to maximize the amount and efficiency of power generated by the power generator 60. When the diameter of the down tube 20 exceeds a certain value relative to the up tube 40, it has been discovered that the efficiency of power generation declines as the diameter of the down tube 20 is increased further. There is therefore an optimum in the ratio of the diameter of the down tube 20 relative to the diameter of the up tube 40, and therefore the ratio of the area of the down tube 20 relative to the area up tube 40, in order to maximize the efficiency of power generation. When the ratio of the area of the down tube 20 to the up tube 40 increases beyond the optimal value, the increase in efficiency of power generation with increased fresh water flow in the down tube 20 is less than with a down tube 20 having a smaller area relative to the up tube 40 area. Choosing the diameter of the down tube 20 to maximize power production therefore involves tradeoffs to choose the maximum diameter possible without losing power efficiency.

In the embodiment of the apparatus shown in FIG. 4, the outlet end 24 of the down tube 20 is located inside the up tube 40. In this embodiment, the outlet end 24 of the down tube 20 is preferably oriented so that the outlet end 24 of the down tube 20 points upward.

The up tube 40 has an lower end 42 and an outlet end 44. In the embodiment of FIG. 4 both the lower end 42 and the outlet end 44 of the up tube 40 are open. In other embodiments, the lower end 42 of the up tube 40 may contain vanes or other means of directing water flow. Some of these alternative embodiments of the up tube 40 are illustrated in other figures herein.

Although the diameters of the lower end 42 and the outlet end 44 of the embodiment of the up tube 40 shown in FIG. 4 are equal, the lower end 42 and the outlet end 44 of the up tube 40 may have different diameters in other embodiments. For example, the up tube may be positively or negatively tapered to form a nozzle or diffuser. Alternatively, the up tube 40 can have a necked-down portion to form an accelerated flow there-through.

In the embodiment of FIG. 4 the outlet end 44 of the up tube 40 is attached to a flotation system for locating the up tube 40 at a predetermined depth. Other means of locating the up tube 40 at a predetermined depth may also used in place of the flotation system, and the invention is not limited to the embodiment shown in FIG. 4. The flotation system shown in FIG. 4 comprises one or more floats 48 and one or more support cables 50. The float 48 may be formed of Styrofoam, or it may comprise a plurality of individual air bags, drums, or any other suitable material capable of producing buoyancy.

In some embodiments, the lower end 42 of the up tube 40 is attached to mooring cables 52. The mooring cables 52 extend from the lower end 42 of the up tube 40 to anchors 56 fixed on the sea floor. The mooring cables 52 and the anchors 56 retain the up tube 40 in a predetermined location on the sea floor. The lifting force of the float 48 transmitted through support cables 50 retains the up tube 40 at a desired predetermined vertical orientation.

In the embodiment shown in FIG. 4, the down tube 20 is also attached to mooring cables 52 which extend to anchors 56 on the ocean floor. The mooring cables 52 and anchors 56 hold the down tube 20 in place. The down tube 20 is arranged so that it discharges the fresh water into the up tube 40.

Just as choosing an optimal diameter for the down tube 20 involves tradeoffs, choosing the diameter of the up tube 40 also involves optimization. Increasing the diameter of the up tube 40 increases the amount of upwelling in the up tube 40 and therefore increases power production. However, increasing the diameter of the up tube 40 increases both the size and the cost of the apparatus. Further, increasing the area of the up tube 40 allows the use of a down tube 20 with a greater area without losing efficiency in generating power. The ratio of the area of the down tube 20 to the area of the up tube 40 is therefore the parameter which is to be optimized rather than the diameter of either the up tube 40 or the down tube 20 alone The optimal diameters for the up tube 40 and the down tube 20 are interdependent on one another, because the ratio of the areas of the two tubes is a more important parameter in optimizing power production than the area, and therefore the diameter, or either the up tube 40 or the down tube 20 alone.

Advantageously the down tube 20 and the up tube 40 are not subjected to excessively high pressures. In the embodiment shown in FIG. 4, the up tube 40 contains the sea water entering from the lower end 42 of the up tube 40 and the fresh water coming out of the outlet end 24 of the down tube 20. Because the up tube 40 is operated at low pressures, the up tube 40 can be constructed of relatively inexpensive and lightweight materials such as plastic, PVC, lightweight concrete, and the like.

Although the down tube 20 is subjected to higher pressures than the up tube 40, the pressures in the down tube 20 are typically small. Thus, inexpensive materials can therefore generally be used for both the up tube 40 and the down tube 20. Suitable materials for constructing the down tube 20 and the up tube 40 include, but are not limited to, polyvinyl chloride (PVC), fiberglass, polyethylene (PE), polypropylene (PP), concrete, gunite, and the like. Alternatively, other materials such as stainless steel or titanium may also be used. Because the up tube 20 and the down tube 40 are generally exposed to water of relatively high salinity, it is preferable to form the down tube 20 and the up tube 40 from materials which are resistant to corrosion from salt water. Although the materials listed above are, in general, resistant to corrosion, some alloys of stainless steel are not suitable for extended use in salt water. If stainless steel is chosen as a material of construction, it is preferable to select an alloy of stainless steel which is resistant to corrosion by salt water.

The outlet end 44 of the up tube 40 may extend to or above the surface of the sea or may be located at any depth beneath the surface of the sea. In one embodiment, the outlet end 44 of the up tube 40 is located in the photic zone so as to bring nutrient-rich deep-sea water to the photic zone to enhance growth of the organisms in the photic zone through mariculture.

The length of the up tube 40 may vary, depending on a variety of factors. The length of the up tube is preferably sufficient to allow complete mixing of the fresh water with the salt water, but not so long as to cause unnecessary drag on the water flow. The optimal length will be determined as that which allows maximum output flow rate and power production for a given range of input fresh-water flow rates. The length of the up tube 40 may also be chosen based on a desire to facilitate mariculture, the promotion of growth of organisms in the sea by transfer of nutrients from nutrient-rich depths to the nutrient-poor water at lesser depths. If mariculture is practiced, the lower end 42 of the up tube 40 is preferably located at a depth of the sea where large concentrations of nutrients are available, and the outlet end 44 of the up tube 40 is preferably located in the photic zone. In this embodiment, the up tube 40 carries nutrient-rich water from the depth of the lower end 42 of the up tube 40 to the outlet end 44 of the up tube 40 in the photic zone, where few nutrients are available, thereby enhancing growth of the organisms in the photic zone. The length of the down tube 20 is relatively unimportant, provided that it is long enough to deliver the fresh water into the up tube.

The power generator 60 generates electricity from the water flow inside the up tube 40. FIG. 4 shows one simplified form of a power generator 60 suitable for use with the present invention. The power generator 60 comprises one or more turbines or propellers 62 attached to a shaft 64. In a preferred embodiment, there are a plurality of propellers 62 attached to the shaft 64. The shaft 64 is connected to an electrical generator 66. When water upwells in the up tube 40, the upwelling water turns the propellers 62, which in turn rotate the shaft 64. The rotating shaft 64 drives the electrical generator 66, thereby generating power.

Preferably, one or more shaft supports 68 are provided to support the shaft 64 to minimize wobbling of the shaft 64 while the upwelling water turns the one or more propellers 62 attached to the shaft 64. In a preferred embodiment, a plurality of shaft supports 68 engage the shaft 64 to support the shaft 64 to minimize wobbling. In the embodiment shown in FIG. 4, three shaft supports 68 are present to support the shaft 64, a lower shaft support 68, a middle shaft support 68, and an upper shaft support 68. Further details on the shaft supports 68 are given in FIG. 7C, described later.

The propellers 62 on the shaft 64 may be inside the up tube 40, above the outlet end 44 of the up tube 40, or both inside the up tube 40 and above the outlet end 44 of the up tube 40. The propellers 62 on the shaft 64 may be located above the middle shaft support 68, below the middle shaft support 68, or both above and below the middle shaft support 68. In the embodiment of FIG. 4, the propellers 62 are located inside the up tube 40 below the middle shaft support 68. Similarly, the electrical generator 66 may be conveniently located above or below the surface of the water in which the up tube 40 is located. In the embodiment shown in FIG. 4, the electrical generator 66 is located above the surface of the water in order to minimize maintenance expense.

FIG. 5 shows an alternative embodiment of a power generator 60. In this case, the power generator 60 comprises propellers 62 attached to the shaft 64 both above and below the middle shaft support 68. The shaft 64 is attached to the electrical generator 66, which generates electrical power when the shaft 64 rotates due to the water flow in the up tube 40. Again, the electrical generator 66 of FIG. 5 is located above the surface of the water. In alternative embodiments, the electrical generator 66 may be located below the surface of the water, if desired.

FIG. 6 shows a further alternative embodiment of a power generator 60 in which one or more spiral fans 70 are mounted on the shaft 64. Shaft supports 68 may optionally be provided to minimize wobbling of the shaft 64. The one or more spiral fans 70 may be attached to the shaft 64 above the middle shaft support 68, below the middle shaft support 68, or both above and below the middle shaft support 68. One or more spiral fans 70 may be mounted on the shaft 64 on the outlet end 44 of the up tube 40. In an alternative embodiment, one or more spiral fans 70 may be mounted both inside the up tube 40 and on the outlet end 44 of the up tube 40. In the embodiment of FIG. 6, the spiral fan 70 is attached to the outlet end 44 of the up tube 40.

The spiral fan 70 comprises a plurality of spiral vanes 72. The water flow up the up tube 40 contacts the plurality of spiral vanes 72, turning the one or more spiral fans 70 mounted on the shaft 64. Turning the one or more spiral fans 70 rotates the shaft 64. The rotating shaft 64 drives the electrical generator 66, generating electrical power. Again, the electrical generator 66 may be conveniently located above or below the surface of the water, as desired.

In the embodiment of the power generator 60 shown in FIG. 6, both propellers 62 and one spiral fan 70 are mounted on the shaft 64. The propellers 62 and spiral fans 70 may be mounted on the shaft 64 in any order, above, below, or both above and below the middle shaft support 68. The propellers 62 and spiral fans 70 may also be mounted on the shaft 64 inside the up tube 40 and/or above the outlet end 44 of the up tube 40. In FIG. 6, propellers 62 are mounted on the shaft 64 inside the up tube 40 below the middle shaft support 68, and the single spiral fan 70 is mounted on the outlet end 44 of the up tube 40. The electrical generator 66 is located above the water.

FIG. 7A shows a further alternative embodiment of the up tube 40 in which the lower end 42 of the up tube 40 is closed. The down tube 20 passes through the closed lower end 42 of the up tube 40. Although FIG. 7A shows that the down tube 20 is attached to one or more mooring cables 52 which are attached to anchors 56 on the ocean floor, the down tube 20 may also be supported by the closed lower end 42 of the up tube 40. The closed lower end 42 of the up tube 40 of FIG. 7A helps to keep the down tube 20 in position without the need for mooring cables 52 and anchors 56.

The up tube 40 of the embodiment of FIG. 7A comprises a plurality of slots 76, as shown in FIG. 7B. The plurality of slots 76 are open to the surrounding sea and allow the sea water to enter the up tube 40. One or more shaft supports 68 are attached to the up tube 40; One possible embodiment of a suitable shaft support 68 is shown in FIG. 7C. The shaft support 68 comprises one or more hydrodynamic cross members 78 and a bearing 80. The cross members 78 are attached to the up tube 40 at a first end and to the bearing 80 at a second end, thereby suspending the bearing 80 inside the up tube 40. The bearing 80 can have a variety of designs such as ball bearings, compression bearings, and the like. The cross members 78 are preferably hydro-dynamically shaped so as to not slow down water flow in the up tube 40. The shaft support 68 supports the shaft 64, minimizing the wobbling of the shaft 64 when the shaft 64 rotates.

The power generator 60 of the embodiment shown in FIG. 7A comprises a vane drum 90 inside the up tube 40. The vane drum 90 comprises a plurality of rings 92 connected by a plurality of curved vanes 94. FIG. 7D shows a sectional view of the vane drum 90. Each curved vane 94 is attached by a first edge 96 to each of the plurality of rings 92. The curved vanes 94 are attached to the plurality of rings 92 in a manner so that the curved vanes 94 form a helical curve when viewed from the side, as shown in FIG. 7A. The helical curved shape of the curved vanes 94 improve the efficiency of energy transfer from the water flow through the slots 76 on the up tube 40 compared to the efficiency of curved vanes 94 which are not oriented with a helical curve. FIG. 7D shows the curved vanes 94 attached to the ring 92 from above as illustrated in FIG. 7A. FIG. 7D also shows the preferred curved surface of the curved vanes 94 as well as the helical orientation of the curved vanes 94 as viewed from above.

In one preferred embodiment, the vane drum 90 is attached to the shaft 64. When the sea water is drawn into the up tube 40 through the slots 76, the incoming water contacts the curved vanes 94, rotating the vane drum 90, which in turn rotates the shaft 64. The rotating shaft 64 turns the electrical generator 66, generating power from the upwelling water in the up tube 40.

FIG. 8A illustrates a further alternative embodiment of the power generator 60 comprising two vane drums 90, a first vane drum 90 below the middle shaft support 68 and a second vane drum 90 above the middle shaft support 68. In a preferred embodiment, both the first vane drum 90 and the second vane drum 90 are attached to the shaft 64 so that the shaft 64 rotates when the vane drums 90 rotate due to the flow of water through the slots 76 into the up tube 40. The rotating shaft 64 rotates the shaft of the electrical generator 66, generating electrical power.

In the embodiment of the up tube 40 shown in FIG. 8B, there are preferably two sets of slots 76 in the up tube 40 and two vane drums 90. In another embodiment, there are two vane drums 90 as in the embodiment shown in FIG. 8A, but the up tube 40 comprises only a single set of slots 76 in the up tube 40, as in the embodiment of the up tube 40 shown in FIG. 7B.

FIG. 9A shows an alternative embodiment of the down tube 20 in which a plurality of holes 110 are present in the side of the down tube 20. FIG. 9B shows a view of the outlet end 24 of the down tube 20 of FIG. 9A. The outlet end 24 of the down tube 20 of FIG. 9A is sealed except for a single hole 110. In alternative embodiments, a plurality of holes 110 may be provided in the outlet end 24 of the down tube 20. The fresh water flowing through the down tube 20 of FIG. 9A flows out of the plurality of holes 110 and into the up tube 40. Although the embodiment of the apparatus shown in FIG. 9A shows the alternative down tube 20 with the embodiment of the up tube 40 of FIGS. 4-6 with an open lower end 42, the down tube 20 of FIG. 9A may also be used with the embodiment of the up tube 40 such as shown in FIG. 7A or 8A with a closed lower end 42.

FIGS. 10A and 10B show another embodiment of the down tube 20 in which the down tube 20 separates into a plurality of secondary down tubes 120 In the embodiment shown in FIG. 1A, there are a plurality of holes 110 in the secondary down tubes 120, similar to the embodiment of the down tube 20 shown in FIG. 9A. FIG. 10B shows a sectional view of the down tube 20 of the embodiment of FIG. 10A from below. In the embodiment shown in FIG. 10B the outlet end 24 of each of the five secondary down tubes 120 is closed except for a single hole 110. In the embodiment of the down tube 20 of FIGS. 10A and 10B, the fresh water that is introduced into the down tube 20 exits the holes 110 to enter the up tube 40.

In other embodiments the down tube 20 may separate into a plurality of secondary down tubes 120, as in the embodiment of the down tube 20 of FIG. 10A, but there are no holes 110 in the secondary down tubes 120, and the outlet ends 24 of the secondary down tubes 120 are open. In this embodiment of the down tube 20 (not shown), the fresh water which is introduced into the down tube 20 exits the open outlet ends 24 of the secondary down tubes 120 to enter the up tube 40.

FIG. 11 shows an alternative embodiment of the down tube 20 in which the down tube separates into a plurality of secondary down tubes 120. In the embodiment shown in FIG. 11, the down tube 20 separates into a plurality of secondary down tubes 120 outside of the up tube 40. In the embodiment shown in FIG. 11, there are no holes in the secondary down tubes 120, as in the embodiments shown in FIGS. 9A and 10A. In other embodiments there are a plurality of holes 110 in the secondary down tubes 120.

Although the embodiment of the apparatus shown in FIG. 11 shows the alternative down tube 20 with the embodiment of the up tube 40 of FIGS. 4-6 with an open lower end 42, the alternative down tube 20 of FIG. 11 may also be used with the embodiment of the up tube 40 such as shown in FIG. 7A or 8A with a closed lower end 42.

FIG. 12 shows another embodiment of the down tube 20 in which the down tube 20 terminates in a hub 122. The hub 122 forms a cap on the down tube 20 and rotates freely on the down tube 20. A plurality of spoke outlets 124 are fluidly connected to the hub 122. The plurality of spoke outlets 124 emerge at approximately a right angle from the hub 124 and then bend at a second angle before terminating in a spoke discharge 126. The spoke discharge 126 may have an open end or a partially closed end where the water from the down tube 20 discharges. The embodiment of the down tube 20 shown in FIG. 12 is similar to a rotating lawn sprinkler. The hub 122 is attached to the shaft 64, which is in turn connected with the electrical generator 66. In the embodiment shown in FIG. 12, there is no up tube 40.

When fresh water flows through the down tube 20 and is discharged out of the spoke outlets 124, the hub 122, shaft 64, and electrical generator 66 rotate, generating electrical power. In the embodiment shown in FIG. 12, the energy generated by the electrical generator 66 comes almost exclusively from the kinetic energy from the water emerging from the plurality of spoke discharges 126, because there is no up tube 40 or means of generating power from hydrocratic energy generated from the mixing of fresh water from the down tube 20 with water of high salinity.

FIG. 13 shows another embodiment of the down tube 20 similar to the embodiment of FIG. 12, with a hub 122, a plurality of spoke outlets 124, and a plurality of spoke discharges 126 at the ends of the spoke outlets 124. The embodiment of FIG. 13 differs from the embodiment of FIG. 12 in that the spoke discharges 126 discharge the fresh water from the down tube 20 into an up tube 40 with an open lower end 42 and a plurality of propellers 62 attached to the shaft 64. The fresh water which exits the spoke discharges 126 into the up tube 40 causes upwelling in the up tube 40, rotating the propellers, which in turn drive the shaft 64. The shaft 64 drives a electrical generator 66 (not shown), generating electrical power.

In the embodiment of the apparatus shown in FIG. 13, the shaft 64 is rotated both by the discharge of water from the spoke discharges 126 rotating the hub 122 and by the upwelling in the up tube 40 turning the propellers 62, which in turn rotate the shaft 64. The energy generated in the embodiment of the apparatus shown in FIG. 13 is therefore a combination of kinetic energy from the rotation of the hub 122, shaft 64, and electrical generator (not shown) from the fresh water ejected from the spoke discharges 126 and from hydrocratic energy generated from the upwelling in the up tube 40 from the mixing of fresh water from the spoke discharges 126 mixing with the water of high salinity entering the up tube 40 from the lower end 42.

FIG. 14 illustrates another embodiment of the up tube 40 in which there are a plurality of nested up tubes 40 having increasing diameters. The lower end 42 of each of the plurality of nested up tubes 40 is open. Fresh water is introduced into the down tube 20 causing upwelling in the plurality of up tubes 40 when the water of high salinity enters the open lower ends 42 of the nested up tubes 40.

Any of the embodiments of power generators 60 can be combined with the embodiment of the nested up tubes 40 of FIG. 14. For example, in one embodiment, the propellers 62 of FIGS. 4 and 5 may be used as a power generator 60 in combination with the nested up tubes 40 of FIG. 14. In another embodiment, the power generator 60 may comprise one or more spiral fans 70, as shown in FIG. 6.

FIG. 15 shows another embodiment of the up tube 40 and power generator 60. In the embodiment of FIG. 15, a plurality of turbines 130 are mounted on a shaft 64 inter-spaced between a plurality of stators 132. The stators 132 direct the water flow into the turbine blades of the turbines 130 to increase the efficiency thereof. The shaft 64 is connected to an electrical generator 66 (not shown). When water upwells in the up tube 40, the upwelling water turns the turbines 130, which in turn rotate the shaft 64 and the electrical generator 66, generating power.

In the embodiment shown in FIG. 15, the portion of the up tube 40 surrounding the turbines 130 and stators 132 comprises a nozzle 134 and an expander 136. The nozzle 134 reduces the diameter of the up tube 40 in the portion of the up tube 40 around the turbines 130 and stators 132 from the diameter of the remainder of the up tube 40. By reducing the diameter of the up tube 40 with the nozzle 134 in the portion of the up tube 40 surrounding the turbines 130, the upwelling water is forced into a smaller area and is accelerated to a higher velocity water flow that can be harnessed more efficiently by the turbines 130. Nozzles 134 and stators 132 can also be used with other embodiments of the power generator 60 illustrated herein.

FIG. 16 is a schematic illustration of a possible large-scale commercial embodiment of a hydrocratic generator having features and advantages of the present invention. While a particular scale is not illustrated, those skilled in the art will recognize that the device 200 is advantageously suited for large-scale deep-water use 100-500 meters or more beneath sea level. The up tube 240 extends upward and terminates at any convenient point beneath sea level. The diameter of the up tube may be 3-20 meters or more, depending upon the desired capacity of the hydrocratic generator 200. This particular design is preferably adapted to minimize environmental impact and, therefore, does not result in upwelling of nutrient rich water from the ocean depths.

Sea water is admitted into the device from an elevated inlet tube 215 through a filter screen or grate 245. The filter removes sea life and/or other unwanted objects or debris that could otherwise adversely impact the operation of generator 200 or result in injury to local sea life population. If desired, the inlet tube 215 may be insulated in order to minimize heat loss of the siphoned-off surface waters to colder water at or near full ocean depth. Advantageously, this ensures that the temperature and, therefore, the density of the sea water drawn into the generator 200 is not too cold and dense to prevent or inhibit upwelling in the up tube 240.

The sea water is passed through a hydraulic turbine power plant 260 of the type used to generate hydraulic power at a typical hydro-electric facility. The turbine and generator assembly is illustrated in more detail in the cutaway view of FIG. 16. Water enters the turbine 261 through a series of louvers 262, called wicket gates, which are arranged in a ring around the turbine inlet. The amount of water entering the turbine 261 can be regulated by opening or closing the wicket gates 262 as required. This allows the operators to keep the turbine turning at a constant speed even under widely varying electrical loads and/or hydraulic flow rates. Maintaining precise speed is desirable since it is the rate of rotation which determines the frequency of the electricity produced.

As illustrated in FIG. 16, the turbine is coupled to an electric generator 266 by a long shaft 264. The generator 266 comprises a large, spinning “rotor” 267 and a stationary “stator” 268. The outer ring of the rotor 267 is made up of a series of copper wound iron cells or “poles” each of which acts as an electromagnet. The stator 268 is similarly comprised of a series of vertically oriented copper coils disposed in the slots of an iron core. As the rotor 267 spins, its magnetic field induces a current in the stator's windings thereby generating alternating current (AC) electricity.

Referring again to FIG. 16, the sea water is discharged from the turbine into the up tube 240. Fresh water is introduced into the base of the up tube 240 by down tube 220. The mixing of fresh water into saline sea water releases the hydrocratic or osmotic energy potential of the fresh water in accordance with the principles discussed above, resulting in a concomitant pressure drop (up to 190 meters of head) across the hydraulic turbine 260. This pressure drop in conjunction with the induced water flow upwelling through the up tube 240 allows for generation of significant hydropower for commercial power production applications without adversely affecting surrounding marine culture.

With reference to FIG. 18 of the drawings, this embodiment shows an up tube 40 having an open lower end 42 and an open outlet end 44. A down tube 20 is provided which enters the up tube 40 through the lower end 42, and extends to a point approximately midway along the length of the up tube, where it is sealed by a cap 302. A shaft 64 extends upwardly from the cap 302, extending to a generator, not shown in FIG. 18, but substantially similar to generators shown in some of the Figures described above.

Although in the embodiment shown in FIG. 18, the down tube 20 is shown as extending to a point approximately midway up the length of the up tube 40, this construction may, in practice, vary widely according to the conditions, length of the up tube 40, and other apparatus parameters. Thus, the down tube 20 may extend only a short distance into the up tube 40, or it may extend well beyond the midpoint thereof, to a selected height.

The down tube 20 comprises an outside portion 304, located outside of the up tube 40, and an inside portion 306, located within the up tube 40. The outside portion 304 and inside portion 306 of the down tube 20 are connected to each other by a rotational connector 308, which, in the embodiment shown in FIG. 18 is at the level of the open lower end 42. However, this rotational connector 308 could be configured on the down tube 20 at any appropriate vertical position of the down tube 20.

The rotational connector 308 permits rotation of the inside portion 306 relative to the outside portion 304, as will be described.

The inside portion 306 has a plurality of radial apertures 310, which may be randomly disposed on the inside portion 306, or specifically located, such as beneath a turbine 62, according to the selected configuration of the generator. Fresh water entering the down tube 20 from a supply source or reservoir passes through the rotational connector 308, and into the inside portion 306, where it must exit through one of the radial apertures. The cap 302 mounted at the top end of the inside portion 306 prevents any water or liquid from the down tube 20 from exiting the inside portion 306, except through the radial apertures 310.

The inside portion 306 and shaft 64 are secured appropriately in position by shaft supports 68 to prevent wobbling or axial displacement thereof, as has already been described above in other embodiments.

In operation, fresh water exiting the down pipe 20 through the radial apertures 310 is mixed with water of higher salinity entering the lower end 42 of the upper tube 40. The energy produced by the mixing of the water of higher salinity and lower salinity drives turbine 62, which in turn rotates the inside portion 306, the cap 302, and the shaft 64. This embodiment permits accurate selection of apertures 310 for releasing of the fresh water into the up tube 40, in a manner that is fixed with respect to the turbines 62. Since the radial apertures 310 and turbines 62 are both rotating, the precise location of mixing, and the optimal effect thereof of driving the turbine 62, can be exploited to improve the efficiency and hence the energy produced by the apparatus of the invention. This is achieved by the use of the rotational connector 308 which allows relative rotation of the inside portion 306, but ensures no leakage or fresh water escape from the down tube 20 at the position of the rotational connector 308.

FIG. 19 shows a variation of the apparatus shown in FIG. 18, including the up tube 40, the down tube 20 having an outside portion 304, and an inside portion 306, the outside and inside portions 304 and 306 respectively being connected by the rotational connector 308. A cap 302 is provided at the top end of the inside portion 306, and a series of turbines 62 are mounted on the inside portion 306, which has a plurality of selectively placed radial apertures 310. The apparatus in FIG. 19 differs from the embodiment shown in FIG. 18 by the existence of a closure piece 320 over the lower end 42 of the up tube 40. Since the closure piece 320 prevents sea water from entering the lower end 42 of the up tube 40, a plurality of holes 322 are provided at locations in the wall of the up tube 40, as shown in FIG. 19B, through which the sea water is introduced to the interior of the up tube 40. One advantage of the embodiment shown in FIGS. 19A and 19B is that the sea water can be introduced at the most efficient point, thereby facilitating control of the precise points or areas at which the sea water as well as the fresh water are first introduced and allowed to mix. This factor, coupled with the orientation of turbines 62 on the inside portion 306, can be used to streamline the efficiency of the apparatus. As was the case with respect to FIG. 18, the fresh water is only allowed to exit through the radial apertures between the rotational connector 308 and the cap 302, at a position, flow-rate and orientation which can be controlled and manipulated to advantage.

In FIG. 20 of the drawings, a further embodiment showing a variation of those illustrated in FIGS. 18 and 19 of the drawings is illustrated. In this embodiment, an up tube 40 is provided, as well as a down tube 20 including an outside portion 304, an inside portion 306 having a plurality of radial apertures 310, and a cap 302. At the lower end 42, a closure piece 320 is provided. In the embodiment shown in FIG. 20, the rotational device 308 is positioned outside of the up tube 40 and closure piece 320 so as to permit rotation of both the inside portion 306 of the down tube 40, and the up tube 20, in response to energy production which causes rotation of the turbine 62. Thus, rotation about the connector 308 as a result of forces on the turbines 62 thereby rotates the closure piece 320, up tube 40 and the inside portion 306 of the down tube 20.

As was the case in the embodiment shown in FIGS. 19A and 19B, sea water will enter the up tube 40, not through the lower end 42, but through a series of holes 322 of the type shown in FIG. 19B. Alternatively, instead of having a plurality of holes 322, one or more slits may be provided in the wall of the up tube 40, such as those shown in FIG. 7B or 8B of the drawings.

The embodiment of FIG. 20 is yet another variation by means of which the precise location of entry of the fresh water and sea water respectively into the up tube 40 can be controlled and exploited to derive maximum energy and power following hydrocrasis and the energy released thereby.

FIG. 21 of the drawings shows a variation of the hydrocratic generator of the invention which uses neither vanes nor turbines on the shaft 64, but rather a helical screw 330 mounted on the shaft, and which is caused to rotate in response to the energy released by mixing of the water with different salinities. Such forces acting on the helical screw 330 rotate the shaft 64, which in turn transmits rotational forces to the generator for use as described above.

FIG. 22A of the drawings shows an alternative embodiment for delivering fresh water from the down tube 20 to a precise location with respect to the fan blades. As shown in FIG. 22A, an inside portion 306 of the down tube 20 has a plurality of fan blades 62, also referred to as turbines, mounted thereon Instead of exiting the inside portion 306 through a plurality of apertures, the fresh water in the inside portion 306 is fed through a fan tube 336 which is mounted on the underside 338 of the fan blade 62. Towards the outer extremity 340 of the fan blade 62, the fan tube 336 includes a U-shaped section 342, terminating in an outlet 344. Thus, fresh water enters through the inside portion 306, flows along the fan tube 336, into the U-shaped section 342, and exits through outlet 344. In the embodiment shown in FIGS. 22A and 22B, the fresh water thus flows from the interior pipe through a series of smaller pipes located under the fan blades 62 (or helical screw, if this embodiment is used), to the outer edge of the fan blades 62. The direction of flow is reversed so the fresh water exits in a flow direction which is towards the center of the up tube 40.

The embodiment shown in FIGS. 22A and 22B allows the apparatus to take advantage, once more, of controlling the exit areas for the saline and fresh water, thereby pinpointing the reaction location for maximum energy production and/or use of such energy in a manner which rotates the fan blades optimally. As with the other embodiments, the inside portion 306 of the down tube 20 is attached to a rotating shaft, which in turn attaches to a generator or power mechanism which uses or stores the energy so produced.

Reference is now made to FIG. 23 of the drawings showing yet a further schematic representation of an embodiment of the invention. FIG. 23 shows some of the basic components only, and is mainly intended to illustrate the various locations and multiple turbines which may be used with the system. As such, only the basic apparatus is shown, but it may of course incorporate features and components as described in any one or more of the previous embodiments This also applies to all embodiments described below.

In FIG. 23, the up tube 400 is positioned within a body of water 402, the up tube 400 having an upper end 404 and a lower end 406. Typically, the body of water 402 is the ocean, and water of relatively high humidity will enter the up-tube 400 through the lower end 406, and move towards the upper end 404. However, other models and variations are of course within the scope of this invention.

A down tube 408 is provided, and extends from a reservoir 410 at one end, with the other end 412 of the down pipe/tube discharging into the up tube 400 at or near the lower end 406. As has been described above, water from the reservoir 410 will have relatively low salinity, and mix with the relatively high salinity water entering through the lower end 406 of the up tube 400. As has already been described, the mixing of the relatively low and relatively high salinity water produces energy, and power generators are positioned to capture this energy. In FIG. 23, a first turbine 414 is provided near the upper end 404 of the up tube 400 to capture the energy and therefore generate power. It is to be noted that a second turbine 416 is positioned near the reservoir 410, along the down tube 408. Note that the second turbine 416 is shown near the reservoir 410 in FIG. 23, but it may be placed at other locations along the down tube 408. The flow of water through the down tube 408 drives the second turbine 412 and energy derived therefrom is used to produce power.

Additionally, a third turbine 418 is provided near the lower end 406 of the up tube 400. The third turbine 418 is positioned so as to take advantage of flow of water from the body of water 402 into the up tube 400, and capture and produce power.

Thus, it will be seen from FIG. 23 that various turbines may be placed around the system to take advantage of water flow not only as the result of the mixing of the relatively low and relatively high salinity water, but also to place turbines in other positions where they may be driven by the flow of water, either through the down tube 408, or upon entering or being driven through the up tube 400. Note that in FIG. 23, the second turbine 416 is shown outside of the body of water 402, although of course it can be placed at a lower level along the down tube 408, and may additionally or alternatively be located in the body of water 402.

In FIG. 24 a of the drawings, another mechanism whereby water may be introduced from a source of low salinity into the up tube is illustrated. Thus, in very schematic form, FIG. 24 a shows an up tube 430, positioned substantially vertically, with an upper end 432 and a lower end 434, as has already been described. Water of relatively high salinity enters the lower end 434, passes into the up tube 430, and eventually is discharged through the upper end 432. While in the up tube 432, the relatively high salinity water is mixed with a relatively low salinity water delivered by a down pipe or tube 436. The down pipe 436 is connected to a source of relatively low salinity water, and extends to the lower end 434 of the up tube 430, and has a discharge opening 438 through which the relatively low salinity water is introduced into the up tube 430.

Further, the down pipe 436 has attached thereto a secondary down pipe 440 which leads off the down pipe 436 and is spirally or helically wrapped around the up tube 430. The secondary down pipe 440 has a plurality of holes 442 arranged along its length, and these holes register with corresponding holes in the up tube to permit water to pass from the secondary down pipe 440, through the up tube 430 and into the interior thereof. FIG. 24 b shows a cross-section of the secondary pipe 440, wrapped around the up-tube 430, with the holes 442. In this embodiment, therefore, the relatively low salinity water, or fresh water, is introduced into the up-tube 430 not only at the low end 434 thereof, but also along multiple points of entry corresponding to the holes 442. This may facilitate mixing in a more thorough manner and may therefore also enhance the ability to capture additional power as a result thereof.

Reference is now made to FIG. 25 which shows a further embodiment of the invention in schematic form. Once more, there is provided an up tube 450, and a down pipe 452. The up tube 450 has a lower end 454 and an upper end 456. The up tube 450 is located in a body of water, such as the ocean, and relatively high salinity water enters through the lower end 454, passes through the up tube 450 and is discharged through the upper end 456.

The down pipe 452 conveys water from a fresh water source, or water of relatively low salinity, or waste water which has been, or is to be treated, therethrough, and comprises the discharge opening 458 near the low end 454 of the up tube 450. Additionally, a sleeve 460 is formed around the up tube 450, and is supplied with water from the down pipe 452 through a branch pipe 462. The branch pipe 462 conveys water from the down pipe 452 to the inside of the sleeve 460, and holes in the up tube 450 allow water introduced into the sleeve 460 to enter the up tube 450 for mixing with the relatively high salinity water entering through the lower end 454. It will be appreciated that this embodiment shows a variation of that shown in FIG. 24 a, providing additional points of entry of fresh water, or relatively low salinity water, to enhance mixing over a wider volume.

FIG. 26 illustrates a further embodiment of the invention in schematic form, and shows an up tube 470 having an upper end 472 and a lower end 474. A down pipe 476 conveys fluid of relatively low salinity into the lower end 474 of the up tube 470. Additionally, a first branch pipe 478 and a second branch pipe 480 branch from the down pipe 476, and have discharge outlets 482 and 484 respectively within the up tube 470. The down pipe 476 itself continues and has a discharge outlet 486 near the lower end 474 of the up tube 470. FIG. 26 illustrates an embodiment where fluid is delivered to the up tube 470 at several locations, once more, to facilitate mixing and to enhance the ability to capture additional power from the mixing process.

In FIG. 27, an up tube 490 has an upper end 492 and a lower end 494. A down tube 496 extends from a source of relatively low salinity water, and has a discharge outlet 498 near the lower end 494 of the up tube 40. The down tube 496 also has a first branch pipe 497 and s second branch pipe 500 which respectively connect to a ring 502 and a ring 504 which circumnavigates the up tube 490 at various locations along its length. The first and second branch pipes 497 and 500 respectively deliver water or fluid to the rings 502 and 504 respectively, and the rings 502 and 504 have multiple holes therein through which water can pass to enter the up tube 490. FIG. 27 b is cross-section through the up tube at the location of a ring, providing a further detail as to the configuration. Once more, this particular form of the invention allows a more diverse delivery of low salinity fluid into the up tube 490 to provide a more broad-based and effective mixing mechanism which in turn facilitates capturing of additional power from the mixing process.

Reference is now made to FIG. 28 of the drawings showing in schematic form yet another embodiment of the invention. In this particular embodiment, the hydrocratic generator of the invention is intended for use in conjunction with, for example, a sanitation district which may optionally incorporate a desalination plant. In FIG. 28, there is shown a body of water 520 having a water surface 522. Within the body of water 520, there is located a vertical or up tube 524 having an open upper end 526 and an open lower end 528. The up tube 524 is preferably located adjacent a land mass 530, which has built thereon various structures, including a sanitation district plant 532 and a desalination plant 534. These two plants provide, respectively, fluid of relatively high salinity, and fluid of relatively low salinity, so that the mixing thereof within the vertical tube 524, along the lines described in the several embodiments above, produce energy which can be captured by a power generator for storage and subsequent use.

A sewer line 538 extends from the sanitation district plant 532, and has a discharge outlet 540 at or near the lower end 528 of the vertical tube 524. There is also a pipe or brine line 542 for transmitting fluid from the desalination plant to the inside of the up tube 524. Within the tube, the discharge contents from the sewer line 538, and the brine line 542, each of which has different relative salinity levels, results in a mixture which produces energy. A power generator, which may be in the form of a turbine, is not shown in FIG. 28 of the drawings, but may be positioned at or near the upper end 526 of the vertical tube 524, so as to capture the energy of the mixture. Additionally, turbines or power generators may be placed at other locations, such as in either one of the sewer line 538 or brine line 542.

As an alternative, the brine line 542 and sewer line 538 may be juxtaposed so that each discharges into the vertical tube in the reverse form as shown in FIG. 28. The lower end 528 of the vertical tube 524 is open, so that water from the body of water 520, such as an ocean, also enters the vertical tube.

In FIG. 28, the turbine or power generator may be above the upper end 526, outside of the vertical or up tube 524, or it may be at the level of the upper end 526 or even below it within the tube. Further, there may be more than one turbine or power generators arranged relative to the tube 524 so as to maximize the capture power in the most efficient manner to optimize energy produced by the mixing of the various fluids.

It should be noted that in all of the embodiments above, the relatively low salinity fluids and the relatively high salinity fluids may comprise fresh water and ocean water respectively, but the invention is certainly not limited to such an arrangement. In fact, the hydrocratic generator of the invention may be used in any situation which can exploit the energy produced by the mixing of relatively low salinity fluid and relatively high salinity fluid, irrespective of their nature. Thus, the fluid may be fresh water, ocean water, desalinated water, sanitation or waste water, or any other fluid, without limitation, the combination of which with one other such fluid will produce the necessary energy by virtue of mixing.

FIG. 29 shows a further embodiment of the invention. The hydrocratic generator 560 comprises a top tube 562 and an lower tube 564. The top tube 562 has open upper and lower ends 566 and 568. The lower tube 564 also has open upper and lower ends 570 and 572. The top tube 562 has a turbine 574 at or near its lower end 568. The top tube 562 is of smaller dimension than the lower tube 564 so that the lower end 568 of the top tube 562 is received with in the upper open end 570 of the lower tube 564. A brine line 576 feeds the top tube 562. There is a gap between the lower tube 564 and the lower end 568 of the top tube 562. This gap is preferably sufficiently large so that the percentage at the bottom of the lower tube will about 36% ppt or less.

FIG. 30 shows a hydrocratic generator 580 having a top tube 582 and a lower tube 584. These tubes are arranged more or less as the top tube 562 and lower tube 564 are shown in FIG. 29 of the drawings. There may of course be dimensional variations in the sizes and relative sizes of the top and lower tubes. In FIG. 30, there is a first portion 586 of a brine line 588, and second portion 590 of the brine line 588. These portions are demarcated generally by a head 592. The second portion 590 of the brine line 588 extends into the top tube 582 and has a plurality of holes 594 along its length. The head is shown in a different view in FIG. 31 of the drawings. A turbine 596 is located at or near the lower end of the top tube 582.

In the embodiments shown in FIGS. 29 and 30 of the drawings, the lower end of the top tube preferably extends a short distance downwardly of the upper end of the bottom tube and a gap is provided therebetween.

Reference is now made to FIG. 34 of the drawings, which shows a hydrocratic generator contained in a pool 600. The pool 600 comprises a chamber 602 defined by side walls 604. A hydrocratic generator 606 is shown in schematic form, and is located within the chamber 602 of the pool 600. As seen in FIG. 35 of the drawings, the hydrocratic generator 606 is mounted on a supporting structure 608, which may be adjustable, and which places the hydrocratic generator 606 in a predetermined and preselected space within the pool, as may be determined to be an optimal position.

A cooling water/waste water discharge inlet 610 conveys the cooling water/waste water into the chamber 602, and, as best seen in FIG. 35. The inlet 610 comprises an end 614. The end 614 is approximately at the open end of the inlet 616 of the hydrocratic generator. The discharge 612 passes through the inlet 610, and exits the inlet 610 at the open ended inlet 616 of the hydrocratic generator.

A separate brine conduit 620 conveys brine therethrough from a source and into the pool 600. The brine fills the chamber 602, and rises to a level which is above that of the hydrocratic generator 606. The level of the discharge 612 is such that the hydrocratic generator 606 is located completely within the discharge 612.

It will therefore be appreciated that the pool is essentially filled with the brine conveyed from a source. Cooling water/waste water discharge passes through the inlet 610, and exits therefrom near the open-ended inlet 616 of the hydrocratic generator. As the cooling water/waste water exits the inlet 610, it draws in brine from the pool surrounding the hydrocratic generator 606, as indicated by arrows 622 and 624. AS such, a mixture of cooling water/waster water discharge and brine enters the hydrocratic generator 606, and the difference in osmotic potential, as already described in detail above, is used to drive a turbine 626. The turbine is connected to a generator 630 where the power may be stored, channeled or otherwise disposed of in a large number of different ways.

FIG. 34 shows a side view of the hydrocratic generator illustrated in FIG. 34 of the drawings. As will be seen in both FIGS. 34 and 35 of the drawings, the brine in the pool, as well as the mixture exiting the hydrocratic generator at end 632, eventually exits the pool 600, and is discharged to the ocean through discharge pipe 634.

Reference is now made to FIGS. 32 and 33 of the drawings which show a system somewhat similar to that illustrated and described in FIGS. 34 and 35, where the various structures are essentially the same, except as will be described below. In FIG. 34, the pool is filled with brine, and the cooling water/waste water discharge exits the inlet 610 at the open-ended inlet 616 of the hydrocratic generator 606. In contrast, the embodiment shown in FIGS. 32 and 33 of the drawings show a pool 600 which is filled with cooling water/waste water discharge which enters through the pipe 610, and fills the pool to a level above the position of the hydrocratic generator. In FIGS. 32 and 33, the brine conduit 620 discharges the brine at the open end 615 of the hydrocratic generator 606. In the hydrocratic generator, a mixture of both brine and the cooling water/waste water discharge travel, and provide the necessary osmotic potential to drive the turbine 626, which produces power stored in the generator 630.

In the embodiments shown in FIGS. 32 and 33 on the one hand, and FIGS. 34 and 35 on the other, it will be appreciated that the relative proportions of cooling water/waste water discharge and brine respectively in the hydrocratic generator 606 will differ. Furthermore, the size, diameter, dimensions and other physical attributes of the inlet 610 in FIG. 34 of the drawings may be varied, and the same dimensions and the like of the brine inlet 620 in FIG. 32 may be varied, so that a desired relative proportion of cooling water/waste water discharge and brine is obtained.

In the embodiment shown in FIG. 32 of the drawings, the open end 616 of the hydrocratic generator may be somewhat flared with a frusto-conical wall 638, best seen in FIG. 32 of the drawings.

FIG. 36 of the drawings shows another embodiment, in this case with the hydrocratic generator arranged vertically, as compared with FIGS. 32 to 35, where the hydrocratic generator is mounted in a horizontal or substantially horizontal position. It will be appreciated that mounting of the hydrocratic generator may also be at any suitable angle between vertical and horizontal, as may best be calculated to produce an optimum amount of osmotic potential, and therefore drive the turbine for maximum power output.

In FIG. 36, there is illustrated a closed tank 646, in which is contained a hydrocratic generator 648. The hydrocratic generator has an open lower end 650, and an open upper end 652. Near the open upper end 652, there is mounted a turbine 654, connected to a generator 656, for capturing and storing energy, and has been described previously in this specification, and will not be repeated at this point.

The closed tank 646 is fed by a brine line 658, from which brine from a source is discharged into the closed tank 646. The closed tank 646 is also fed by a cooling water or effluent line 660, which enters through the base of the closed tank 646 and discharges at approximately the level of the lower open end 650 of the hydrocratic generator 648. Both cooling water or effluent discharged through the pipe 660, and brine contained within the closed tank, enter the hydrocratic generator 648, and the osmotic potential produced by the mixing of these two fluids will drive the turbine 654, to provide energy to generator 656 as has been described. The mixture exiting through the upper open end 652 of the hydrocratic generator 648, as well as brine contained within the closed tank, but surrounding the hydrocratic generator 648, are permitted to exit through the overflow or outflow pipe 662.

The closed tank 646 illustrated in FIG. 36 of the drawings may be located on land, or it may be located under water, either fully of partially.

Reference is now made to FIG. 37 of the drawings, which shows an embodiment similar to, but not identical with, that shown in FIG. 36 of the drawings. The structure of the closed tank 646 (reference numerals in FIG. 37 will be the same as those used in FIG. 36, since the structure is essentially identical) is fed with a pipe 658 that injects cooling water or effluent into the close tank. In this embodiment, the pipe 660 feeds brine to the lower open end of the hydrocratic generator 648. The embodiment in FIG. 37 thus shows the reverse use of the cooling water or effluent on the one hand, and the brine on the other, both of which, however, are introduced into the hydrocratic generator to create the osmotic potential for driving the turbine 654. Once more, different proportions or relative amounts of the cooling water or effluence/effluent and brine respectively, may be introduced into the hydrocratic generator depending upon the dimensions, sizes, etc. of the open ends of the hydrocratic generator, as well as the line 660.

Reference is now made to FIG. 38 of the drawings which shows an alternate underwater configuration of the hydrocratic generator illustrated in FIGS. 36 and 37 of the drawings. In FIG. 38, there is shown a tank 678, but with an open top 680. The tank itself may be located either above the ocean, or below the ocean surface. Within the tank there is formed a hydrocratic generator 648, having the turbine 654 and generator 656. In the embodiment shown in FIG. 38, brine is introduced through the pipe 658, while cooling water or effluent is introduced through the pipe 660. However, this could be reversed so that the opposite situation would prevail.

The embodiment shown in FIGS. 32 to 38 may, for example, be optimally used where a desalination plant and a power plant or a sanitation district may be working together. Thus, the sanitation district would pipe the effluent over to the desalination plant, so that at least a portion of effluent from the sanitation runs through the tank, and thereafter becomes incorporated into the overflow which is sent out to sea with the rest of the effluent. The mixture of brine and waste water, as already described with respect to these Figures, drive the hydrocratic generator to generate power.

In one embodiment, a power plant pipes over a portion of the sea water that was used for cooling purposes, to be run through the tank. The overflow then goes back into the outflow line, where it will be run through a desalination device to bring the salinity within less than 4% of the ambient salinity of the sea water and, possibly, generate more power.

More than one such hydrocratic generator of the type described in FIGS. 32 to 38 may be used in combination, wherein, for example only, one hydrocratic generator is formed within a pool on land, and a second hydrocratic generator is formed in the ocean, that generates power from the combined desalination and effluent and/or waste water.

Reference is now made to FIG. 39 of the drawings which shows a down tube 702 having an upper end 704 and a lower end 706, the down tube 702 being hollow and open at each of its ends 704 and 706. A turbine or propeller 708 is shown near the lower end 706 of the down tube 702. The turbine 708 can be of many different configurations, formats and embodiments as has been discussed with respect to other Figures in this application and specification.

Above the down tube 702 there is shown schematically a brine line 710.

At selected points along the down tube 702 there are formed at least one, but preferably a plurality, of openings 712, with each of the openings having adjacent thereto a cup or scoop 714. The cup 714 has an open upper end 716, so that fluid can flow from the ambient, or area surrounding the down tube, through the open end 716, in the opening 712, and into the interior of the down tube 702.

The down tube 702 is typically located in an ambient solution 718, and typically the salinity of the ambient solution 718 will be less than the salinity of the brine entering through the brine line 710.

In FIG. 40 of the drawings, a down tube 720 is schematically illustrated, with similar components and structure to that in FIG. 39. To the extent possible, the same reference numerals have been used to describe the same features and elements. The down tube 720 illustrated in FIG. 40 of the drawings has, as will be observed, a tapering effect, wherein the diameter of the down tube 720 at the lower end 706 is less than the diameter of the down tube at the upper end 704. In this particular embodiment shown in FIG. 40 there is a fairly consistent taper from the upper end 704 to the lower end 706, but it is within the scope of the invention that the degree or extent of tapering may vary along the length of the down tube, and, further, that the tapering may occur only along certain sections, while other sections may be of substantially consistent diameter.

FIG. 41 of the drawings shows yet a further embodiment of a down tube which may be constructed in accordance with the present invention. FIG. 41 shows a down tube 722, and once more, to the extent possible, corresponding reference numbers for corresponding components will be used, as was done in FIGS. 39 and 40.

In FIG. 41, the down tube 722 tapers from a wider diameter upper end 704 to a lesser diameter lower end 706, and the plurality of cups or scoops 704 are distributed at selected locations on the outer side of the down tube 722.

In FIG. 41, there is also shown a series of successively wider down tube elements 724, comprising an upper down tube element 726 and a lower down tube element 728, the lower down tube element 728 being of substantially consistent diameter, but of greater diameter than the upper down tube element 726, also of fairly consistent diameter. Note that the upper and lower down tube elements 726 and 728 may also be tapered, and may either increase in diameter from upper end to lower end, or decrease in diameter from upper end to lower end.

Note that the down tube elements 724 shown in FIG. 41 of the drawings are used with a down tube 722 of decreasing diameter, as shown also in FIG. 40, but it is important to note that the down tube element 724 may also be used with the down tube 702 which has a diameter of substantially consistent size over its length.

As illustrated in FIGS. 39, 40 and 41, the down tubes have openings or perforations 712 at various locations with the cup or scoops 714 optionally located over the openings 712. Some or all of the openings 712 may be present without the cup 714. The cup 714 and opening 712 arrangement is constructed for the purpose of increasing the volume of ambient solution 718 which enters the down tubes 702, 720 and 722.

With respect to these Figures, each hydrocratic engine may typically have fixed interior dimensions. Thus, as the water traveling through the hydrocratic engine, or down tube, increases, the velocity of the water will also increase. As such, the tapering designs of the down tube(s) may have the desired effect of increasing the volume of water passing through the down tube over a given period of time, at the same time increasing the velocity of the water and the amount of power produced by the hydrocratic engine. It will be appreciated of course, that increase of volume and velocity of water passing over the turbine or generator 708 will drive the turbine 708 with increased energy so that more power can be produced.

Reference is now made to FIG. 42 of the drawings showing a further embodiment of a hydrocratic generator, constructed in accordance with one aspect of the invention. As will be seen in the drawing, the hydrocratic generator comprises a chamber 730 defining an upper space 732 and a lower space 734. The upper and lower spaces 732 and 734 being separated by wall 736. A down tube 738 is located within the upper space 732, and comprises a tapering configuration with an upper end 740 having a larger diameter than the lower end 742. The wall of the down tube 738 has at least one and preferably a plurality of openings 744.

The wall 736 has an opening 746, and the lower end 742 of the down tube 738 has a portion which extends through this opening 746, in a manner such that a seal is formed between the wall of the down tube 738 and the wall 736. As will be described below, any fluid contained in the space 732 will not be able to move or pass through the opening 746, which will be sealed in an appropriate manner with the down tube 738.

The upper space 732 of the chamber 730 has a brine inlet 748 and a fresh water inlet 750. The brine inlet has a discharge nozzle 752 which is located immediately above the upper end 740 of the down tube 738. The upper space 732 also has an overflow outlet 754 near the upper end thereof.

In the lower space 734 of the chamber 730, there is constructed an impeller 756 which is attached to a drive shaft 758, the drive shaft itself being attached to a generator 760. The drive shaft 758 extends through the wall of the chamber 730, since, as will be seen in FIG. 42, the generator 760 is located outside of the chamber.

The lower space 734 has a drain outlet 762, and may in one embodiment connect to the overflow outlet 754, which may have a larger diameter, so that either overflow from chamber 730, or discharge from lower space 734 are conveniently removed through the same structure. It will, however, be appreciated that the drain outlet 762 may discharge independently of the overflow outlet 754.

In operation, the hydrocratic generator as shown in FIG. 42 operates when fresh water is introduced into the upper space 732 through the fresh water inlet 750. Eventually, the upper space 732 fills with fresh water, and may fill up to level 764, after which excess fresh water overflows into the overflow outlet 754 for discharge into the ocean. At the same time, brined fluid is introduced through the brine inlet 748, and the nozzle 752 is below level 764. The brine discharged through the nozzle 752 enters into the down tube 738. As the brine fluid moves down through the down tube 738 it is mixed with fresh water which enters the down tube either through the open upper end 740 of the down tube, and/or through one of the plurality of openings 744. The mixing has the effect already described in previous embodiments of the invention, and the mixture is discharged through a nozzle 766 located at the very lower end of the down tube 738, into the lower space 734. As the mixture exits the nozzle 766, the mixture drives the propeller 756 which in turn, through the drive shaft 758, powers the generator 760, which in turn is able to store and thereafter transmit power in the usual way as described. The mixture of fluid entering the lower space 734 ultimately drains through the drain outlet 762 located in the floor of the chamber 730, and is discharged to the ocean either through a separate outlet, or by joining with the overflow outlet 754, as already described.

Note that the down tube 738 in FIG. 42 is shown in a tapered configuration, but this down tube 738 may be of fairly uniform diameter in other configurations, or tapered in the opposite direction. Further, the existence of the opening 744 as well as their number, shape and size, can vary in accordance with the invention. Furthermore, at least some of the openings 744 may have attached thereabout the cup or scoop as has been described and illustrated with respect to FIGS. 39, 40 and 41 of the drawings. It should also be noted that the down tube 738 in FIG. 42 is not to scale, and the Figure is schematic for the purposes of illustrating the components and overall structure of the invention.

Reference is now made to FIG. 43 of the drawings showing a further aspect of the invention. The hydrocratic generator shown in FIGS. 43 and 44 are for most purposes the same, except for the location thereof. FIG. 43 shows a hydrocratic generator of the invention when mounted or contained within a substantially closed reservoir, while FIG. 44 shows the hydrocratic generator of generally the same structure when located in the ocean.

In FIGS. 43 and 44 there is shown a hydrocratic generator including a down tube, generally designated with the reference numeral 770. The down tube 770 is generally in a substantially vertical orientation. The down tube 770 has a number of portions, as will now be described.

The down tube 770 has a funnel portion 772 at the top thereof, with a wider diameter open end 774, tapering down to a narrower lower end 776. At the lower end, the funnel portion 772 transitions with a circular tube portion 778. The generally round or circular tube portion 778 transitions to a square tube portion 780, with a transition 782 therebetween. At the lower end of the square portion 780, there is formed a venturi tube portion 784, with a transition 786 formed there between. The venturi tube portion 784 tapers from a wide diameter end 788 to a narrow diameter end 790, the venturi tube portion 784 having a discharge opening 792 at its narrow end 790.

A brine inlet line 794 transmits brine to the down tube 770 and has a discharge opening 796 just above the open end 774 of the funnel portion 772.

It will be noted that the square tube 780 has at least one, and preferably a plurality of openings 798 through which water from the ambient area around the down tube 770 can be drawn into the down tube 770.

With specific reference to FIG. 43, the down tube 770 as described above is formed within a reservoir 800, having side walls and at least a base wall. There is a fresh water inlet 802 for allowing fresh water into the reservoir 800, and an overflow outlet 804 for overflow. A portion of the venturi tube 784 portion extends through an opening 806 in the lower wall of the reservoir 800, and the mixture of liquids discharged from the opening 792 is used to drive an impeller, turbine or the like, as has been described with reference to other embodiments.

In FIG. 44 of the drawings, the down tube 770 is formed within the ocean 808, but is otherwise of fairly similar construction to that shown in FIG. 43.

In the down tube illustrated in both FIGS. 43 and 44, brine enters the funnel portion 772 of the down tube 770, and flows through the down tube towards the discharge opening 792. The brine liquid is mixed with fresh water, or ocean water, as the case may be, the mixture driving the liquid outwardly form the discharge opening for the purposes of powering a turbine or other appropriate device, as has been described.

Reference is now made to FIG. 45 of the drawings. In FIG. 45, a hydrocratic generator 814 is shown including a down tube indicated generally by the reference numeral 816. In FIG. 45 the down tube 816 is generally cylindrical and of fairly consistent diameter along its length. However, it may be tapering of the down tube 816 along its length, or a portion thereof.

The down tube 816 has a meshed screen portion 818, and a substantially solid portion 820. At the lower end of the solid portion there is formed a turbine 822, impeller or other device by means of which the energy produced within the down tube can be harnessed.

It will be seen that the down tube 816 shown in FIG. 45 is formed in the ocean 824, below the surface 826 thereof. However, it should also be understood that a down tube 816 having the construction and configuration of that as illustrated in FIG. 45 may also be formed in a body of fresh water.

At the upper end of the down tube there is provided a brine line 828 having a discharge opening 830 which discharges brine immediately above the upper end of the down tube. Thus, brine enters the down tube 816 at the top thereof and through the open end, the brine water in the down tube thus having a higher concentration of solutes than in the surrounding ocean water 824. As such, hydrocratic forces cause water from the ocean 824 to pass through the meshed screen portion 818 into the down tube 816, such movement being facilitated by the lower concentration of solute to the higher concentration solute respectively. In FIG. 45, the down tube 816 has a fixed diameter and the additional water passing through the mesh screen portion 818, introduced into the down tube, results in an increasing velocity of the water passing and moving through the down tube 816, thereby increasing the kinetic energy of the water in the hydrocratic engine. These hydrocratic forces will, at least to a large extent, prevent interior water, or water mixture flowing within the down tube 816, from exiting the down tube 816 through the meshed screen portion 818, and into the ocean. Such prevention of flow will occur up to a back pressure point, and this point may be selected and determined based on various parameters including, but not limited to sizes and dimensions of the down tube 816, respective concentrations of the brine and ocean water respectively, as well as such other determining factors.

Other Applications/Embodiments

In the preferred embodiments discussed above, the up tube 40 is located in a body of water of high salinity and high negative osmotic potential such as an ocean or a sea. The water of high salinity and high negative osmotic potential enters the up tube 40 in a ratio of greater than 8:1 salt water to fresh water, more preferably 30:1 salt water to fresh water, and most preferably about 34:1 or higher. The mixing of the fresh water of low negative osmotic potential with the sea water of high negative osmotic potential in the up tube 40 causes upwelling and draws sea water into the up tube 40 through the openings. The upwelling water in the up tube 40 rotates propellers 62, spiral fans 70 or turbines 130, 261, which are attached to a drive shaft 64, 264. The rotating shaft 64, 264 turns the electrical generator 66, 266 generating electrical power from the difference in osmotic potential between the fresh water introduced into the down tube 20 and the water of high salinity which enters the up tube 40 through the openings in the up tube 40.

Because the method depends on having solutions of different osmotic potentials exiting the down tube 20 and entering the up tube 40, it is preferable that the source of fresh water exiting the down tube 20 and the source of the water of high salinity entering the up tube 40 continue to have different osmotic potentials over time so that power generation continues over a long period of time. For example, if the body of water of high salinity surrounding the up tube 40 is small, the fresh water exiting the down tube 20 can dilute the water of high salinity after exiting the up tube 40, reducing the difference in osmotic potential between the fresh water and the water of high salinity. Reducing the difference in osmotic potential between the fresh water exiting the down tube 20 and the water of high salinity entering the up tube 40 reduces the amount of energy available. It is therefore generally advantageous that the body of water of high salinity have a large volume. Locating the up tube 40 in a large body of water having high salinity such as the ocean or the Great Salt Lake is therefore a preferred embodiment.

Alternatively, the invention can be operated between bodies of salt water having different salinity or between waters at different depths of the same body of water. For example, the salinity and temperature of sea water is known to vary with depth and location. In the Hawaiian islands, at a depth of 1000 meters, the ambient water temperature is approximately 35° F., with a salinity of approximately 34.6 ppt. The surface temperature is approximately 80° F. with a salinity of approximately 35.5 ppt. Thus, an osmotic energy potential (albeit small) exists between the surface waters and the waters at 100 meters depth.

While the present invention is disclosed in the context of generating power by directly contacting and mixing fresh water with sea water in an apparatus located in the ocean, it is to be understood that the apparatus and method are not limited to this embodiment. The techniques and concepts taught herein are also applicable to a variety of other situations where aqueous solutions having differing osmotic potentials are available. For example, in one embodiment, the apparatus and method may be applied to a concentrated brine from a desalinization plant being mixed with the less-concentrated brine in sea water. In another embodiment, a treated sewage effluent, a fresh water stream, can be mixed with sea water. If desired, an osmotic membrane or osmotic water exchange plenum may be provided at the outlet end of the down tube and/or at the outlet (top) of the up tube in order to increase the efficiency of energy production. The apparatus and method may thus be applied to a wide range of applications in which two solutions of differing osmotic potential are available.

The various embodiments of the invention disclosed and described herein are exemplary only. As such, these example embodiments are not intended to be exhaustive of all possible ways of carrying out the invention or even the most economical or cost-efficient ways of carrying out the invention on a commercial scale. Accordingly, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow. 

1. A mixing apparatus for mixing first salinity fluid with a second salinity fluid, the mixing apparatus comprising: a down tube having a side wall, an open upper end and an open lower end, and a plurality of apertures selectively located in the side wall of the down tube, at least some of the apertures having an arm member with an opening therein about the aperture to facilitate inflow of fluid to the down tube through the openings; a fluid inlet and a fluid outlet at the open upper end and open lower end respectively of the down tube, wherein the first salinity fluid in use enters the down tube through the fluid inlet and the apertures and is discharged therefrom through the fluid outlet; and a feed tube having a first end connectable to a source of second salinity fluid having a salinity different to the first salinity fluid and a second end for introducing the second salinity fluid to the fluid inlet of the down tube to mix the first salinity fluid with the second salinity fluid to form a fluid mixture.
 2. A mixing apparatus as claimed in claim 1 further comprising at least one power generator associated with the down tube, the power generator being driven by the mixing of the first salinity fluid with the second salinity fluid.
 3. A mixing apparatus as claimed in claim 2 wherein the power generator comprises a plurality of propellers and a shaft, the propellers being located in the housing, and an electrical generator coupled to the shaft for generating electrical power.
 4. A mixing apparatus as claimed in claim 1 wherein the second salinity fluid is selected from the group consisting of ocean water, fresh water, waste water, desalination water, or a mixture of one or more thereof.
 5. A mixing apparatus as claimed in claim 1 wherein the first salinity water is selected from the group consisting ocean water, waste water, or a mixture thereof.
 6. A mixing apparatus as claimed in claim 1 wherein the down tube tapers from a first diameter upper end to a second diameter lower end, the first diameter being greater than the second diameter.
 7. A mixing apparatus as claimed in claim 1 wherein a portion of the down tube comprises at least two substantially co-axial cylindrical elements.
 8. A mixing apparatus as claimed in claim 7 wherein at least some of the cylindrical elements are of different diameter and the cylindrical elements are arranged descending from the upper end of the down tube by increasing diameter.
 9. A mixing apparatus as claimed in claim 1 wherein the arm member comprises a cup shaped member fastened to the down tube about an aperture thereon with the opening of the cup shaped member facing upwardly. 